420 



ATT HEY A 



GENUS 88. ATTHEYA WEST, i860 



Fig. 138. At they a decora, 



Frustules cylindrical, annu- 

 late, slightly elongated, flattened; 

 valves elliptic, having a central 

 nodule, and furnished with two 

 bristles at the apices. 



A single species. 



Attheya decora, West. (T.M.S., iS5o, viii., p. 152, pi. 7, f. 15* 



Characteristics of the genus. 



Marine. Normandy (Brel). !) England (West), Creswell R. Taylor!), Tynemouth (R. 

 Taylor!), Surface of Dee (Stolt.). 



Mr. Peragallo, at page 1 1 of his monograph, says : 



On the margins of the valve may be seen two lines or sutures, which, 

 parting from the central umbilicus, pass under the bristles, so that the valve 

 in reality consists of two calyptras coupled together. The sutural lines of 

 the frustule follow this direction, and are inflected at their middle. 



In my opinion, and until otherwise determined, the Attheya ought to be 

 considered as the longitudinal juxtaposition of two Rhizosolenia. It is a 

 transition between a true Rhizosolenia and a C/uetoceros. 



1 1. Eucii.*;tocere/E. Frustules not consistingof numerous 

 annuli. 



GENUS 89. CH^ETOCEROS EHR. (1844). Char, emend. 



Valves convex, elliptic or circular, furnished with very elongated 

 arms. Frustules generally united into long cylindrical filaments. 



